Titanium-based quantum dot nano-composite high-performance water lock removing agent and preparation method thereof

Abstract

The invention discloses a titanium-based quantum dot nano-composite high-performance water block removing agent and a preparation method, and the water block removing agent is prepared from the following raw materials in percentage by weight: 0.03 to 0.1 percent of amphiphilic titanium quantum dots, 0.2 to 0.4 percent of ampholytic surfactant, 0.05 to 0.2 percent of anionic-nonionic surfactant, 0.1 to 0.2 percent of cosolvent, 0.1 to 0.3 percent of foam inhibitor and the balance of water, wherein the amphiphilic titanium quantum dots are prepared by the following steps: hydrolyzing and condensing a titanate coupling agent through a hydrothermal method to form titanium-based quantum dots, then carrying out primary modification through a silane coupling agent, and then carrying out secondary surface in-situ polymerization modification by using a functional monomer, so as to obtain the amphiphilic titanium quantum dots. The functional monomer is a hydrophobic monomer, acrylic acid and a temperature-resistant and salt-resistant monomer. The water lock removing agent can move deeply without reservoir damage, can reduce the surface tension of deionized water to 19.3 mN / m, and shows excellent water lock removing performance.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas field development, and specifically relates to a titanium-based quantum dot nano-composite high-performance water-decomposing and locking agent and a preparation method thereof. Background Art

[0002] Water seepage during the production process or in the later stage of gas wells causes some seepage channels to be blocked due to water lock, resulting in a gradual decrease in gas production. At the same time, for low-permeability gas reservoir conditions such as the Ordos Basin, hydraulic fracturing is a key measure to improve reservoir conditions and increase production and efficiency. However, during the post-fracturing flowback process, the water lock effect is a key factor affecting the efficiency of fracturing fluid flowback, and it is also one of the main causes of reservoir damage in the near-wellbore area. Therefore, removing water lock is an effective way to restore reservoir seepage conditions, reduce damage and maintain gas well production capacity. The main cause of water lock is that the capillary resistance caused by the excessive gas-water surface tension and part of the condensate-water interfacial tension blocks the gas flow channel. It can be seen that only by reducing the surface / interfacial tension of the water phase can the purpose of removing water lock be achieved.

[0003] Therefore, most common water-locking agents are mainly surfactants, including anionic, nonionic, amphoteric, gemini, and pseudo-tetrasodium surfactants. However, in order to further improve the surface activity of water-locking agents, the surface tension reduction performance of water-locking agents is improved by compounding different types of surfactants. Among them, functional nanomaterials and surfactants have significant synergistic effects and have been widely studied as efficient water-locking agents. However, conventional nanomaterials are limited by particle size and native dispersibility, and it is difficult to exert their due performance in low permeability reservoirs. Summary of the invention

[0004] In view of the defects of the prior art, the present invention prepares and modifies titanium quantum dots by a hydrothermal method, and synergistically enhances surfactant fluid to form a titanium-based quantum dot nanocomposite high-performance water-locking agent, and also provides a preparation method thereof.

[0005] A titanium-based quantum dot nanocomposite high-performance water-locking agent, which is composed of the following raw materials by weight, calculated as 100%: 0.03-0.1% amphiphilic titanium quantum dots, 0.2-0.4% amphoteric surfactants, 0.05-0.2% anionic-nonionic surfactants, 0.1-0.2% cosolvents, 0.1-0.3% antifoaming agents, and the balance water; Among them, the amphiphilic titanium quantum dots are prepared by the following method: first, a titanate coupling agent is hydrolyzed and condensed by a hydrothermal method to form titanium-based quantum dots, then modified once by a silane coupling agent, and then a secondary surface in-situ polymerization modification is performed using functional monomers, wherein the functional monomers are hydrophobic monomers, acrylic acid, and temperature-resistant and salt-resistant monomers.

[0006] Preferably, the amphiphilic titanium quantum dots are prepared by the following method: (1) Under stirring, a titanate coupling agent is dropped into an activator and stirred to obtain solution A. Solution A and polyethylene glycol 2000 are dissolved in ethanol, stirred evenly, reacted at 130 - 180 °C for 2 - 4 h, washed with absolute ethanol, filtered, and dried to obtain titanium-based quantum dot nanometer powder; (2) Under ultrasonic and stirring conditions, the titanium-based quantum dot nanometer powder is added to an aqueous solution of ethanol, the pH is adjusted to 10, and an ethanol solution of a silane coupling agent is dropped therein. The mixture is refluxed and reacted at 50 - 60 °C for 12 - 18 h. After the reaction, it is extracted with petroleum ether and dried to obtain a silane coupling agent-modified titanium-based quantum dot nanometer powder; (3) Under ultrasonic and stirring conditions, the silane coupling agent-modified titanium-based quantum dot nanometer powder and a dispersant are added to deionized water, the functional monomer is added thereto, the pH is adjusted to 7 - 8, and then an aqueous solution of an initiator is added thereto. After stirring evenly, the mixture is refluxed and reacted at 50 - 60 °C for 3 - 5 h, extracted with ethyl acetate, and dried to obtain amphiphilic titanium quantum dots.

[0007] Preferably, in step (1), the ratio of the titanate coupling agent, activator, polyethylene glycol 2000, and ethanol is (5 - 8) mL: 4 mL: (0.8 - 1.2) g: 100 mL; The titanate coupling agent is one of tetra-isopropyl titanate or n-butyl titanate; The activator is a 1 - 5 wt% hydrochloric acid aqueous solution, a 20 - 25 wt% glacial acetic acid aqueous solution, or a 20 - 25 wt% lactic acid aqueous solution.

[0008] Preferably, in step (2), the mass of the silane coupling agent is 10 - 15% of the mass of the titanium-based quantum dot nanometer powder; The silane coupling agent is any one of vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-aminoethyl-3-aminopropyltriethoxysilane, N-aminoethyl-3-aminopropyltrimethoxysilane; The content of ethanol in the aqueous solution of ethanol is 80 - 85 wt%.

[0009] Preferably, in step (3), the mass of the functional monomer accounts for 15-20% of the mass of the silane coupling agent-modified titanium-based quantum dot nanometer powder, the mass of the initiator accounts for 15-20% of the mass of the functional monomer, and the mass of the dispersant accounts for 0.8-1.5% of the total mass of the silane coupling agent-modified titanium-based quantum dot nanometer powder, deionized water, and the functional monomer; The dispersant is any one of Tween 20, Tween 60, Tween 80, and dodecyl polyoxyethylene ether; The initiator is any one or two of ammonium persulfate, ammonium sulfite, potassium persulfate, potassium sulfite, sodium persulfate, sodium sulfite, and hydrogen peroxide.

[0010] Preferably, based on the total mass of the functional monomer being 100%, the addition ratios of the hydrophobic monomer, acrylic acid, and temperature- and salt-resistant monomer are 20-25%: 50-60%: 20-25%; The hydrophobic monomer is any one of dodecyl dimethyl allyl ammonium chloride, tetradecyl dimethyl allyl ammonium chloride, hexadecyl dimethyl allyl ammonium chloride, octadecyl dimethyl allyl ammonium chloride, and octadecyl methacrylate; The temperature- and salt-resistant monomer is at least one of 2-acrylamide-2-methylpropanesulfonic acid, vinylbenzenesulfonic acid, vinylsulfonic acid, N-vinylpyrrolidone, and acrylmorpholine; Preferably, the drying is carried out by drying at 48-60 °C for 12-18 h; the power of the ultrasonic wave is 300 W; in step (2), a 20-25 wt% ammonia water solution is added dropwise to adjust the pH to 10; in step (3), a 2-5 wt% sodium hydroxide water solution is added dropwise to adjust the pH to 7-8; the filtration in step (1) is dialysis or centrifugation.

[0011] More preferably, the dialysis uses a dialysis bag with a molecular weight of 3 kDa, the dialysis time is 4-6 h each time, and dialysis is carried out 4-6 times.

[0012] More preferably, the rotation speed of the centrifugation is 6000-8000 rpm.

[0013] Preferably, the amphoteric surfactant is any one of oleic acid amide propyl betaine, oleic acid amide propyl hydroxysulfobetaine, hexadecyl hydroxysulfobetaine, hexadecyl propyl betaine, erucic acid amide propyl betaine, and erucic acid amide propyl hydroxysulfobetaine.

[0014] The anionic-nonionic surfactant is any one of sodium dodecyl polyoxyethylene ether sulfate, fatty alcohol polyoxyethylene ether sulfonate, and sodium dodecyl polyoxyethylene ether carboxylate.

[0015] Preferably, the defoaming agent is any one of polyoxyethylene polyoxypropylene pentaerythritol ether, polyoxyethylene polyoxypropylene alkanolamine ether, and polyoxypropylene glycerol ether.

[0016] The cosolvent is at least one of isopropanol, methanol, propylene glycol, and glycerol.

[0017] The preparation method of the titanium-based quantum dot nano composite high-performance water block remover: At room temperature, under the state of ultrasonic and stirring, the amphiphilic titanium quantum dots are uniformly dispersed in water, then the cosolvent is added thereto under the stirring state, after stirring evenly, the amphoteric surfactant, anionic-nonionic surfactant, and defoaming agent are sequentially added thereto, and stirred until dissolved.

[0018] Advantages of the present invention: In the present invention, the titanate coupling agent is hydrolyzed by a hydrothermal method to prepare titanium-based quantum dot nanoparticles, and then modified to obtain titanium-based quantum dots with a particle size of 2-6 nm, having obvious fluorescence characteristics. Acting synergistically with the surfactant, the prepared water block remover can migrate deep and cause no reservoir damage, and can reduce the surface tension of deionized water to 19.3 mN / m, showing excellent water block removal performance. Description of the drawings

[0019] Figure 1 It is a high-resolution transmission electron microscope picture of titanium quantum dot nanoparticles.

[0020] Figure 2 It is a particle size distribution diagram of titanium quantum dot nanoparticles.

[0021] Figure 3 It is the fluorescence phenomenon of titanium quantum dot nanofluid. Detailed implementation manners

[0022] Example 1 1. A titanium-based quantum dot nano composite high-performance water block remover is composed of the following raw materials in weight content based on 100%: 0.03% of amphiphilic titanium quantum dots, 0.3% of amphoteric surfactant oleic acid amide propyl betaine, 0.1% of anionic-nonionic surfactant sodium dodecyl polyoxyethylene ether carboxylate, 0.1% of cosolvent glycerol, 0.2% of defoaming agent polyoxyethylene polyoxypropylene alkanolamine ether, and the balance is deionized water; Among them, the amphiphilic titanium quantum dots are prepared by the following method: (1) Under stirring, 8 mL of titanium tetraisopropoxide was dropped into 4 mL of 25 wt% aqueous acetic acid solution and stirred to obtain solution A. Solution A and 1 g of polyethylene glycol 2000 were dissolved in 100 mL of ethanol, stirred evenly, transferred to a polytetrafluoroethylene high-temperature and high-pressure reaction kettle, reacted at 150 °C for 3 h, washed 3 times with absolute ethanol, filtered 5 times through a 3 kDa dialysis bag, with each filtration time being 5 h and changing water, and then dried at 50 °C for 18 h to obtain titanium-based quantum dot nano powder; (2) Under ultrasonic treatment with an ultrasonic power of 300 W and simultaneous stirring, 2 g of the titanium-based quantum dot nano powder was taken and added to 90 mL of an aqueous solution of 80 wt% ethanol. 20 wt% aqueous ammonia solution was added dropwise to adjust the pH to 10. 10 mL of an ethanol solution containing 0.3 g of 3-aminopropyltrimethoxysilane was added dropwise thereto, and the mixture was refluxed at 55 °C for 14 h. After the reaction, it was extracted 3 times with petroleum ether and dried at 60 °C for 12 h to obtain silane coupling agent-modified titanium-based quantum dot nano powder; (3) Under ultrasonic treatment with an ultrasonic power of 300 W and simultaneous stirring, 1 g of the silane coupling agent-modified titanium-based quantum dot nano powder and 1 g of dispersant Tween 60 were added to 40 g of deionized water. 0.05 g of octadecyl methacrylate, 0.1 g of acrylic acid, and 0.05 g of 2-acrylamido-2-methylpropanesulfonic acid were added thereto in sequence, and deionized water was added to make the total mass of the solution 100 g. 2 wt% aqueous sodium hydroxide solution was used to adjust the pH to 7.5, and then 2 mL of an aqueous solution containing 0.04 g of potassium persulfate was added thereto, stirred evenly, refluxed at 50 °C for 5 h, extracted with ethyl acetate, and dried at 50 °C for 18 h to obtain amphiphilic titanium quantum dots.

[0023] 2. The preparation method of the titanium-based quantum dot nano composite high-performance water-lock remover is as follows: At room temperature, under ultrasonic and stirring conditions, the amphiphilic titanium quantum dots are evenly dispersed in water, and then a cosolvent is added thereto under stirring. After stirring evenly, an amphoteric surfactant, an anionic-nonionic surfactant, and an antifoaming agent are added thereto in sequence and stirred until dissolved; wherein, the power of the ultrasonic is 300 W.

[0024] Example 2 The content of the amphiphilic titanium quantum dots is 0.05%, and the others are the same as in Example 1.

[0025] Example 3 The content of the amphiphilic titanium quantum dots is 0.07%, and the others are the same as in Example 1.

[0026] Example 4 The content of the amphiphilic titanium quantum dots is 0.1%, and the others are the same as in Example 1.

[0027] Example 5 1. A high-performance water-lock releasing agent based on titanium-based quantum dot nanocomposite, calculated by 100%, is composed of raw materials with the following weight contents: amphiphilic titanium quantum dots 0.05%, amphoteric surfactant oleic acid amide propyl hydroxysulfobetaine 0.4%, anionic-nonionic surfactant fatty alcohol polyoxyethylene ether sulfonate 0.2%, co-solvent isopropanol 0.2%, defoaming agent polyoxyethylene polyoxypropylene pentaerythritol ether 0.3%, and the balance is deionized water; Among them, the amphiphilic titanium quantum dots are prepared by the following method: (1) Under stirring, 5 mL of titanium tetraisopropoxide is dropped into 4 mL of 5 wt% hydrochloric acid aqueous solution and stirred to obtain solution A. Solution A and 0.8 g of polyethylene glycol 2000 are dissolved in 100 mL of ethanol, stirred evenly, transferred to a polytetrafluoroethylene high-temperature and high-pressure reaction kettle, reacted at 130 °C for 4 h, washed 3 times with absolute ethanol, centrifuged and filtered at a rotation speed of 6000 rpm, and then dried at 48 °C for 18 h to obtain titanium-based quantum dot nanometer powder; (2) Under ultrasonic treatment with an ultrasonic power of 300 W and simultaneous stirring, 2 g of the titanium-based quantum dot nanometer powder is taken and added to 90 mL of an aqueous solution of 85 wt% ethanol, the pH is adjusted to 10 by dropping 25 wt% ammonia aqueous solution, 10 mL of an ethanol solution containing 0.2 g of vinyltrimethoxysilane is dropped into it, and the reaction is refluxed at 50 °C for 18 h. After the reaction is completed, it is extracted 3 times with petroleum ether and dried at 48 °C for 18 h to obtain silane coupling agent-modified titanium-based quantum dot nanometer powder; (3) Under ultrasonic treatment with an ultrasonic power of 300 W and simultaneous stirring, 1 g of the silane coupling agent-modified titanium-based quantum dot nanometer powder and 0.8 g of dispersant Tween 80 are added to 40 g of deionized water. 0.03 g of dodecyl dimethyl allyl ammonium chloride, 0.09 g of acrylic acid, and 0.03 g of vinylbenzenesulfonic acid are added to it in turn, and deionized water is added to make the total mass of the solution 100 g. The pH is adjusted to 7 with 5 wt% sodium hydroxide aqueous solution, and then 2 mL of an aqueous solution containing 0.03 g of ammonium sulfite is added to it, stirred evenly, refluxed at 60 °C for 3 h, extracted with ethyl acetate, and dried at 48 °C for 18 h to obtain amphiphilic titanium quantum dots.

[0028] 2. The preparation method of the high-performance water-lock releasing agent based on titanium-based quantum dot nanocomposite is the same as that in Example 1.

[0029] Example 6 1. A high-performance water-lock release agent based on titanium-based quantum dot nanocomposite, calculated as 100%, is composed of raw materials with the following weight contents: amphiphilic titanium quantum dots 0.1%, zwitterionic surfactant cetyl hydroxysulfobetaine 0.2%, anionic-nonionic surfactant sodium dodecyl polyoxyethylene ether sulfate 0.05%, cosolvent methanol 0.15%, defoaming agent polyoxypropylene glycerol ether 0.1%, and the balance is deionized water; Among them, the amphiphilic titanium quantum dots are prepared by the following method: (1) Under stirring, 8 mL of titanium tetraisopropoxide was dropped into 4 mL of 20 wt% lactic acid aqueous solution and stirred to obtain solution A. Solution A and 1.2 g of polyethylene glycol 2000 were dissolved in 100 mL of ethanol, stirred evenly, transferred to a polytetrafluoroethylene high-temperature and high-pressure reaction kettle, reacted at 180 °C for 2 h, washed 3 times with absolute ethanol, filtered 4 times through a 3 kDa dialysis bag, with each filtration time being 6 h and changing water, and then dried at 60 °C for 12 h to obtain titanium-based quantum dot nanometer powder; (2) Under ultrasonic treatment with an ultrasonic power of 300 W and simultaneous stirring, 2 g of the titanium-based quantum dot nanometer powder was taken and added to 90 mL of an aqueous solution of 80 wt% ethanol, and 20 wt% ammonia water solution was added dropwise to adjust the pH to 10. Then, 10 mL of an ethanol solution containing 0.3 g of γ-methacryloxypropyltrimethoxysilane was added dropwise, and the mixture was refluxed at 60 °C for 12 h. After the reaction, it was extracted 3 times with petroleum ether and dried at 60 °C for 12 h to obtain silane coupling agent-modified titanium-based quantum dot nanometer powder; (3) Under ultrasonic treatment with an ultrasonic power of 300 W and simultaneous stirring, 1 g of the silane coupling agent-modified titanium-based quantum dot nanometer powder and 1.5 g of dispersant Tween 80 were added to 40 g of deionized water. Then, 0.05 g of octadecyl dimethyl allyl ammonium chloride, 0.1 g of acrylic acid, and 0.05 g of N-vinyl pyrrolidone were added thereto in sequence, and deionized water was added to make the total mass of the solution 100 g. The pH was adjusted to 8 using 2 wt% sodium hydroxide aqueous solution, and then 2 mL of an aqueous solution containing 0.03 g of hydrogen peroxide solution was added thereto, stirred evenly, refluxed at 55 °C for 4 h, extracted with ethyl acetate, and dried at 60 °C for 12 h to obtain amphiphilic titanium quantum dots.

[0030] 2. The preparation method of the high-performance water-lock release agent based on titanium-based quantum dot nanocomposite is the same as that in Example 1.

[0031] Example 7 1. A high-performance water-lock releasing agent based on titanium-based quantum dot nanocomposite, calculated as 100%, is composed of raw materials with the following weight contents: amphiphilic titanium quantum dots 0.03%, amphoteric surfactant erucyl amidopropyl betaine 0.3%, anionic-nonionic surfactant sodium dodecyl polyoxyethylene ether carboxylate 0.05%, co-solvent propylene glycol 0.1%, defoaming agent polyoxyethylene polyoxypropylene amine ether 0.1%, and the balance being deionized water; Among them, the amphiphilic titanium quantum dots are prepared by the following method: (1) Under stirring, 6 mL of titanium tetraisopropoxide was added dropwise to 4 mL of 1 wt% hydrochloric acid aqueous solution and stirred to obtain solution A. Solution A and 1 g of polyethylene glycol 2000 were dissolved in 100 mL of ethanol, stirred evenly, transferred to a polytetrafluoroethylene high-temperature and high-pressure reaction kettle, reacted at 150 °C for 3 h, washed 3 times with absolute ethanol, centrifuged and filtered at a rotation speed of 8000 rpm, and then dried at 50 °C for 18 h to obtain titanium-based quantum dot nanometer powder; (2) Under ultrasonic treatment with an ultrasonic power of 300 W and simultaneous stirring, 2 g of the titanium-based quantum dot nanometer powder was taken and added to 90 mL of an aqueous solution of 80 wt% ethanol. 20 wt% ammonia water solution was added dropwise to adjust the pH to 10. 10 mL of an ethanol solution containing 0.2 g of N-aminoethyl-3-aminopropyltriethoxysilane was added dropwise thereto, and the mixture was refluxed at 60 °C for 14 h. After the reaction, it was extracted 3 times with petroleum ether and dried at 60 °C for 12 h to obtain silane coupling agent-modified titanium-based quantum dot nanometer powder; (3) Under ultrasonic treatment with an ultrasonic power of 300 W and simultaneous stirring, 1 g of the silane coupling agent-modified titanium-based quantum dot nanometer powder and 1 g of dispersant Tween 60 were added to 40 g of deionized water. 0.05 g of tetradecyl dimethyl allyl ammonium chloride, 0.1 g of acrylic acid, and 0.05 g of acryloylmorpholine were added thereto in sequence, and deionized water was added to make the total mass of the solution 100 g. 2 wt% sodium hydroxide aqueous solution was used to adjust the pH to 7.5, and then 2 mL of an aqueous solution containing 0.04 g of ammonium sulfite was added thereto, stirred evenly, refluxed at 50 °C for 5 h, extracted with ethyl acetate, and dried at 50 °C for 18 h to obtain amphiphilic titanium quantum dots.

[0032] 2. The preparation method of the high-performance water-lock releasing agent based on titanium-based quantum dot nanocomposite is the same as that in Example 1.

[0033] Comparative Example 1 The content of amphiphilic titanium quantum dots is 0, and the others are the same as in Example 1.

[0034] Performance detection I. Detection of amphiphilic titanium quantum dots in Example 1 1. Transmission electron microscope detection The amphiphilic titanium quantum dots in Example 1 were detected by transmission electron microscopy, and the results are shown in Figure 1 .

[0035] 2. Particle size detection The software Image J was used to statistically analyze the particle size of the amphiphilic titanium quantum dots in Example 1, and the results are shown in Figure 2 .

[0036] As shown by Figure 1 and 2 , the synthesized titanium quantum dots are granular, have good dispersibility, uniform size distribution, and a median particle size of 3.5 nm.

[0037] 3. Fluorescence property detection The fluorescence properties of the amphiphilic titanium quantum dots in Example 1 were detected using a dark box ultraviolet instrument, and the results are shown in Figure 3 . As shown by Figure 3 , it exhibits typical blue fluorescence properties, confirming that it is a quantum dot nanofluid.

[0038] II. Surface tension detection of the water blockage remover At room temperature, the pendant drop method module of a high temperature and high pressure interfacial tensiometer was used to measure the surface tension of the sample. The water blockage remover sample was aspirated into a syringe, and a drop of liquid was ejected and suspended in the air. The surface tension was calculated by fitting the shape of the liquid drop, and the value was taken after the curve was stable. The detection results are shown in Table 1.

[0039] Table 1 Surface tension detection results Water lock inhibitor Concentration of amphiphilic titanium quantum dots / % Surface tension / mN / m Comparative Example 1 0 27.2 Example 1 0.03 21.5 Example 2 0.05 20.1 Example 3 0.07 19.3 Example 4 0.1 19.4 Example 5 0.05 19.1 Example 6 0.1 19.3 Example 7 0.03 20.5 From the data in Table 1, it can be seen that the surface tension of the liquid decreases significantly after adding the amphiphilic titanium quantum dots. Compared with not adding the amphiphilic titanium quantum dots, when the addition amount of the amphiphilic titanium quantum dots in Example 3 reaches 0.07%, the surface tension decreases from 27.2 mN / m to 19.3 mN / m. It can be seen that the amphiphilic titanium quantum dots can cooperate with the surfactant to play an excellent role in removing water blockage.

Claims

1. A titanium-based quantum dot nanocomposite high-performance water-locking agent, characterized in that: Based on 100%, it is composed of the following raw materials in weight content: 0.03-0.1% of amphiphilic titanium quantum dots, 0.2-0.4% of amphoteric surfactants, 0.05-0.2% of anionic nonionic surfactants, 0.1-0.2% of cosolvents, 0.1-0.3% of antifoaming agents, and the balance of water; Among them, the amphiphilic titanium quantum dots are prepared by the following method: first, a titanate coupling agent is hydrolyzed and condensed by a hydrothermal method to form titanium-based quantum dots, then modified once by a silane coupling agent, and then a secondary surface in-situ polymerization modification is performed using functional monomers, wherein the functional monomers are hydrophobic monomers, acrylic acid, and temperature-resistant and salt-resistant monomers.

2. According to claim 1, a titanium-based quantum dot nanocomposite high-performance water-locking agent, characterized in that: The amphiphilic titanium quantum dots are prepared by the following method: (1) Under stirring, a titanate coupling agent is added dropwise to an activator and stirred to obtain a solution A, and the solution A and polyethylene glycol 2000 are dissolved in ethanol, stirred evenly, reacted at 130-180° C. for 2-4 hours, washed with anhydrous ethanol, filtered, and dried to obtain titanium-based quantum dot nanopowders; (2) adding the titanium-based quantum dot nanopowder to an aqueous solution of ethanol under ultrasonic and stirring conditions, adjusting the pH to 10, adding dropwise an ethanol solution of a silane coupling agent thereto, and reacting under reflux at 50-60° C. for 12-18 hours. After the reaction is completed, extracting with petroleum ether, drying, and obtaining a silane coupling agent-modified titanium-based quantum dot nanopowder; (3) Under ultrasonic and stirring conditions, the silane coupling agent-modified titanium-based quantum dot nanopowder and dispersant are added to deionized water, the functional monomer is added thereto, the pH is adjusted to 7-8, and then an aqueous solution of an initiator is added thereto, the mixture is stirred evenly, refluxed at 50-60° C. for 3-5 hours, extracted with ethyl acetate, and dried to obtain amphiphilic titanium quantum dots.

3. According to claim 2, a titanium-based quantum dot nanocomposite high-performance water-locking agent, characterized in that: In step (1), the ratio of titanate coupling agent, activator, polyethylene glycol 2000 and ethanol is (5-8) mL:4 mL: (0.8-1.2) g:100 mL; The titanate coupling agent is one of tetraisopropyl titanate or n-butyl titanate; the activator is 1-5wt% hydrochloric acid aqueous solution, 20-25wt% glacial acetic acid aqueous solution, or 20-25wt% lactic acid aqueous solution.

4. According to claim 3, a titanium-based quantum dot nanocomposite high-performance water-locking agent, characterized in that: In step (2), the mass of the silane coupling agent is 10-15% of the mass of the titanium-based quantum dot nanopowder; The silane coupling agent is any one of vinyl trimethoxy silane, vinyl triethoxy silane, γ-methacryloxypropyl trimethoxy silane, γ-methacryloxypropyl triethoxy silane, 3-aminopropyl triethoxy silane, 3-aminopropyl trimethoxy silane, N-aminoethyl-3-aminopropyl triethoxy silane, and N-aminoethyl-3-aminopropyl trimethoxy silane; The content of ethanol in the aqueous solution of ethanol is 80-85wt%.

5. According to claim 4, a titanium-based quantum dot nanocomposite high-performance water-decomposing and locking agent, characterized in that: In step (3), the mass of the functional monomer accounts for 15-20% of the mass of the silane coupling agent modified titanium-based quantum dot nanopowder, the mass of the initiator accounts for 15-20% of the mass of the functional monomer, and the mass of the dispersant accounts for 0.8-1.5% of the total mass of the silane coupling agent modified titanium-based quantum dot nanopowder, deionized water, and the functional monomer; The dispersant is any one of Tween 20, Tween 60, Tween 80, and dodecyl polyoxyethylene ether; The initiator is any one or two of ammonium persulfate, ammonium sulfite, potassium persulfate, potassium sulfite, sodium persulfate, sodium sulfite and hydrogen peroxide.

6. The titanium-based quantum dot nanocomposite high-performance water-locking agent according to claim 5, characterized in that: The total mass of the functional monomer is calculated as 100%, and the addition ratio of the hydrophobic monomer, acrylic acid, and the temperature-resistant and salt-resistant monomer is 20-25%: 50-60%: 20-25%; The hydrophobic monomer is any one of dodecyl dimethyl allyl ammonium chloride, tetradecyl dimethyl allyl ammonium chloride, hexadecyl dimethyl allyl ammonium chloride, octadecyl dimethyl allyl ammonium chloride, and octadecyl methacrylate; The temperature-resistant and salt-resistant monomer is at least one of 2-acrylamide-2-methylpropane sulfonic acid, vinylbenzene sulfonic acid, vinyl sulfonic acid, N-vinyl pyrrolidone and acryloylmorpholine.

7. The titanium-based quantum dot nanocomposite high-performance water-locking agent according to claim 5, characterized in that: The drying step is drying at 48-60° C. for 12-18 hours; the ultrasonic power is 300 W; in step (2), 20-25 wt % of an aqueous ammonia solution is added dropwise to adjust the pH to 10; in step (3), 2-5 wt % of an aqueous sodium hydroxide solution is added dropwise to adjust the pH to 7-8; and in step (1), the filtration step is dialysis or centrifugation.

8. The titanium-based quantum dot nanocomposite high-performance water-locking agent according to claim 1, characterized in that: The amphoteric surfactant is any one of oleamidopropyl betaine, oleamidopropyl hydroxysulfonate betaine, hexadecyl hydroxysulfonate betaine, hexadecyl propyl betaine, erucamidopropyl betaine, and erucamidopropyl hydroxysulfonate betaine; The anionic-nonionic surfactant is any one of sodium lauryl polyoxyethylene ether sulfate, fatty alcohol polyoxyethylene ether sulfonate, and sodium lauryl polyoxyethylene ether carboxylate.

9. The titanium-based quantum dot nanocomposite high-performance water-locking agent according to claim 1, characterized in that: The foam suppressor is any one of polyoxyethylene polyoxypropylene pentaerythritol ether, polyoxyethylene polyoxypropanolamine ether and polyoxypropylene glycerol ether; The co-solvent is at least one of isopropanol, methanol, propylene glycol and glycerol.

10. The method for preparing a titanium-based quantum dot nanocomposite high-performance water-decomposing and locking agent according to claim 1, characterized in that: At room temperature, under ultrasound and stirring, the amphiphilic titanium quantum dots are evenly dispersed in water, and then a cosolvent is added thereto under stirring. After stirring evenly, an amphoteric surfactant, an anionic-nonionic surfactant, and an antifoaming agent are added thereto in sequence and stirred until dissolved.

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